Misonix Inc. board member Stavros G. Vizirgianakis, 46, will take over as interim chief executive on Friday, replacing Michael McManus Jr., who is resigning from the board of directors and retiring as president and CEO, the medical device maker announced.

McManus, 73, a former chief executive of New York Bancorp Inc., served for 16 years as chief executive of Misonix, which makes ultrasonic medical devices used to remove damaged tissue from wounds and in spine surgery, neurosurgery and orthopedic surgery.

Over the past 12 months, Misonix shares are down about 46 percent. Shares fell 4.3 percent Monday to close at $6.08.

The Farmingdale company said it is negotiating with Vizirgianakis, who holds a 5.7 percent stake in Misonix, to become permanent chief executive. He is serving as interim CEO on an unpaid basis. His involvement with Misonix began in 2010, when a company he owns began distributing Misonix products in South Africa.

“I am honored to be asked to serve as interim chief executive officer and am excited about the company’s products and future,” he said in a statement.

Under McManus’ retirement agreement, the company will pay his salary through June 30, 2017, at the current level and pay premiums for medical, dental, vision and hospitalization coverage for him and his dependents.

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Vizirgianakis co-founded Surgical Innovations, a medical device distributor in Africa, and has worked for U.S. Surgical Corp. as director of sales for sub-Saharan Africa and for Tyco Healthcare as general manager for South Africa.

For the quarter ended March 31, Misonix posted a net loss of $679,244 on net sales of $5.4 million.